Functional response and life history parameters of Apanteles taragamae, a larval parasitoid of Maruca vitrata

The legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a serious pest of cowpea in West-Africa. The parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) that originates from Taiwan is a potential candidate for biological control of M. vitrata. We investigated under laboratory conditions the functional response of the parasitoid by offering each experienced female 10, 20, 30 and 40 larvae of M. vitrata. We studied the influence of different host larval ages on the development, longevity, sex ratio, lifetime fecundity and parasitization rate of the wasp. In a comparative study, we also investigated the life history of A. taragamae and M. vitrata at different temperatures in the range of 20–30C. The parasitoid successfully parasitized two- and three-day-old host larvae (first and second instars). Younger larvae (one-day-old) were parasitized to a lesser extent, and only males developed in them. Older larvae were not parasitized, partly because of defensive host behaviour. The success of arasitization was positively correlated with the density of two-day-old M. vitrata larvae. Parasitoid developmental time and longevity decreased with increasing temperature. The intrinsic rate of population increase (rm) exhibited an optimum curve with a maximum at 24–28C. For the host M. vitrata, rm was maximal at temperatures of 26–30C. The data are discussed in the context of the potential of A. taragamae for biological control of M. vitrata

Assessing nontarget effects and host feeding of the exotic parasitoid Apanteles taragamae, a potential biological control agent of the cowpea pod borer Maruca vitrata

Article PurchasedApanteles taragamae Viereck is a larval parasitoid introduced in Benin for classical biological control of the cowpea pod borer Maruca vitrata Fabricius. In the laboratory, we evaluated the effects of A. taragamae on non-target herbivore species, and on another parasitoid of M. vitrata, i.e. the egg-larval parasitoid Phanerotoma leucobasis Kriechbaumer. Furthermore, we addressed the host feeding behaviour of A. taragamae. The host specificity of A. taragamae was assessed by offering six other lepidopteran species to the wasp. The competitive ability of A. taragamae was studied by providing the wasp with one- and two-days-old M. vitrata larvae that had hatched from eggs previously parasitized by P. leucobasis. Controls consisted of eggs and larvae offered only to P. leucobasis and A. taragamae, respectively. None of the other six lepidopteran species was successfully parasitized by A. taragamae. The larval parasitoid A. taragamae outcompeted the egg-larval parasitoid P. leucobasis when offered two-days-old host larvae. Competition between the two parasitoid species did not significantly affect one-day-old host larvae that were less suitable to A. taragamae. Host feeding by A. taragamae did not affect survival of one-day-old or two-days-old M. vitrata larvae. However, the percentage parasitism of two-days-old larvae was significantly reduced when exposed to female A. taragamae wasps that had been starved during 48 h. The data are discussed with regard to host specificity, host feeding patterns and to factors underlying the outcome of intrinsic competition between parasitoid species

Transparency you can trust: Transparency requirements for artificial intelligence between legal norms and contextual concerns

Transparency is now a fundamental principle for data processing under the General Data Protection Regulation. We explore what this requirement entails for artificial intelligence and automated decision-making systems. We address the topic of transparency in artificial intelligence by integrating legal, social, and ethical aspects. We first investigate the ratio legis of the transparency requirement in the General Data Protection Regulation and its ethical underpinnings, showing its focus on the provision of information and explanation. We then discuss the pitfalls with respect to this requirement by focusing on the significance of contextual and performative factors in the implementation of transparency. We show that human–computer interaction and human-robot interaction literature do not provide clear results with respect to the benefits of transparency for users of artificial intelligence technologies due to the impact of a wide range of contextual factors, including performative aspects. We conclude by integrating the information- and explanation-based approach to transparency with the critical contextual approach, proposing that transparency as required by the General Data Protection Regulation in itself may be insufficient to achieve the positive goals associated with transparency. Instead, we propose to understand transparency relationally, where information provision is conceptualized as communication between technology providers and users, and where assessments of trustworthiness based on contextual factors mediate the value of transparency communications. This relational concept of transparency points to future research directions for the study of transparency in artificial intelligence systems and should be taken into account in policymaking.Horizon 2020(H2020)707404Article / Letter to editorInstituut voor Metajuridic

Transparency you can trust: Transparency requirements for artificial intelligence between legal norms and contextual concerns

Transparency is now a fundamental principle for data processing under the General Data Protection Regulation. We explore what this requirement entails for artificial intelligence and automated decision-making systems. We address the topic of transparency in artificial intelligence by integrating legal, social, and ethical aspects. We first investigate the ratio legis of the transparency requirement in the General Data Protection Regulation and its ethical underpinnings, showing its focus on the provision of information and explanation. We then discuss the pitfalls with respect to this requirement by focusing on the significance of contextual and performative factors in the implementation of transparency. We show that human–computer interaction and human-robot interaction literature do not provide clear results with respect to the benefits of transparency for users of artificial intelligence technologies due to the impact of a wide range of contextual factors, including performative aspects. We conclude by integrating the information- and explanation-based approach to transparency with the critical contextual approach, proposing that transparency as required by the General Data Protection Regulation in itself may be insufficient to achieve the positive goals associated with transparency. Instead, we propose to understand transparency relationally, where information provision is conceptualized as communication between technology providers and users, and where assessments of trustworthiness based on contextual factors mediate the value of transparency communications. This relational concept of transparency points to future research directions for the study of transparency in artificial intelligence systems and should be taken into account in policymaking.Horizon 2020(H2020)707404Article / Letter to editorInstituut voor Metajuridic

Photonic Crystal-Based Compact High-Power Vacuum Electronic Devices

This paper considers how the finite dimensions of a photonic crystal placed inside a resonator or waveguide affect the law of electron beam instability. The dispersion equations describing e-beam instability in the finite photonic crystal placed inside the resonator or waveguide (a bounded photonic crystal) are obtained. Two cases are considered: the conventionally considered case, when diffraction is suppressed, and the case of direct and diffracted waves having almost equal amplitudes. The instability law is shown to be responsible for increase of increment of instability and decrease of length, at which instability develops, for the case when amplitude of diffracted wave is comparable with that of direct one, that happens in the vicinity of $\pi$-point of dispersion curve. Application of photonic crystals for development of THz sources at electron beam current densities available at modern accelerators is discussed.Comment: 14 pages, 2 eps figures, presented at Channeling 2018, submitted to Physical Review Accelerators and Beam

First report of outbreaks of the fall armyworm Spodoptera Frugiperda (J E Smith) (Lepidoptera, Noctuidae), a new alien invasive pest in West and Central Africa

Article purchasedThe fall armyworm Spodoptera frugiperda is a prime noctuid pest of maize on the American continents where it has remained confined despite occasional interceptions by European quarantine services in recent years. The pest has currently become a new invasive species in West and Central Africa where outbreaks were recorded for the first time in early 2016. The presence of at least two distinct haplotypes within samples collected on maize in Nigeria and São Tome suggests multiple introductions into the African continent. Implications of this new threat to the maize crop in tropical Africa are briefly discussed

Insect fauna associated with Anacardium occidentale (Sapindales: Anacardiaceae) in Benin, West Africa

First published online: 1 January 2014Cashew, Anacardium occidentale L. (Sapindales: Anacardiaceae), is an important cash crop in Benin. However, its production is threatened by several biotic factors, especially insects. In Benin, very few studies have focused on insects and just listed species commonly found on cashew worldwide. The present investigation fills this gap by presenting an exhaustive inventory of insect species associated with this crop in the country. The survey was carried out from September 2009 to August 2010 in 22 cashew orchards (5 young and 17 mature) distributed over three major agroecological zones where cashew is most produced in the country. Insects were collected using chemical knock-down technique and visual observation followed by capture with sweep net. In addition, infested plant organs were sampled and incubated to collect emerging insects. In total, 262 insect species were recorded and identified. Among them, the wood borer Apate terebrans Pallas, the leafminer Eteoryctis gemoniella Stainton, and the mirid bugs Helopeltis schoutedeni Reuter., and Helopeltis anacardii Miller., appeared as the most important insect species attacking cashew in Benin. Beneficial insects encountered included some predators, parasitoids, and pollinators. Few vertebrate predators were also recorded on the trees. Differences in agroecological conditions or in field cleanliness did not affect the number of insect species encountered in the cashew orchards. The results of this study represent an important baseline data for the design and implementation of strategies for cashew protection in Benin

Farmers knowledge, perceptions and management of Kersting’s groundnut (Macrotyloma geocarpum Harms) insect pests in Benin

Open Access JournalBackground Macrotyloma geocarpum Harms is a neglected and underutilized crop in Benin subject to several constraints including storage insect attacks, which contribute to the decrease in its production. An ethnobotanical survey using a semi-structured questionnaire was conducted in 15 villages in southern and central Benin to document farmers’ perceptions of M. geocarpum storage insect pests and their traditional management practices. Results The results showed that insect pest were the most important storage constraint of M. geocarpum. To overcome this constraint, the promotion of resistant landraces has been proposed by farmers. Six vernaculars names of storage insect pests of M. geocarpum were identified throughout the study area and all corresponding to Callosobruchus maculatus (F.) which proved to be the most abundant insect in the stocks. Palatability and fragility of seeds coat have been identified by farmers as the main factors favoring the infestation by this pest. Various storage containers of M. geocarpum have been inventoried. Our study revealed that education, storage containers, and Kersting’s groundnut landraces significantly influenced farmers’ perceptions of severity of insect pest damages. The use of chemicals and repellent plants were the main control methods used by farmers to protect stocks. Different levels of resistance of M. geocarpum landraces to storage insect pests were reported. Conclusions This study provides baseline information for development of integrated management approaches against storage insect pests of M. geocarpum. The perceived level of resistance to insect damage on Kersting’s groundnut landraces needs to be investigated

Repellent effect and insecticidal activities of Bridelia ferruginea, Blighia sapida, and Khaya senegalensis leaves powders and extracts against Dinoderus porcellus in infested dried yam chips

Open Access Article; Published online: 21 June 2017Dinoderus porcellus is considered as the most important pest of stored yam chips and compounds extracted from plants can be used for its control. The present study aimed to test the insecticidal and repellent activities of powders and extracts of leaves of Bridelia ferruginea, Blighia sapida, and Khaya senegalensis against D. porcellus. The efficacy of plant powders was compared with the synthetic pesticide Antouka (Permethrin 3 g/kg + pirimiphos 16 g/kg). The results of the experiment revealed that all plant powders were effective as repellents. Antouka was more effective as insecticidal than the plant powders and minimal weight loss was observed with B. sapida at 2%. Among treatments, propanol extract of K. senegalensis at 5% was found to elicit the highest repellent effect on D. porcellus. The LC50 results revealed that the acetone extract of K. senegalensis is the most toxic (0.29 μL/insect) to the pest, while the propanol extract of B. ferruginea at 5% exhibited strong fumigant toxicity against D. porcellus, with 88.89% of pest mortality at 160 μL/L air. The findings from the current work proved that plant powders and extracts of the three plants are sources of botanical insecticides which may be used in the integrated management of D. porcellus

Comparative Effects of Some Botanical Extracts and Chemicals in Controlling the Red Spider Mite Tetranychus evansi Baker & Pritchard on Solanaceous Crops

The tomato red spider mite, Tetranychus evansi, is an invasive pest reported on solanaceous crops in Benin around 2008, causing heavy economic damage. The control of this mite by farmers is mainly done through intensive applications of chemical pesticides that are not always effective. In the present study, we evaluated in a laboratory, at IITA-Benin, the effects of two botanical insecticides: the Cashew Nut Shell Liquid (CNSL) and Neem oil. This is together with Acarius 18 EC, a chemical acaricide generally used by growers on eggs and adult females T. evansi. The half recommended dose (0.5 l/ha), the recommended dose (1 l/ha), and the double recommended dose (2 l/ha) of Acarius and Neem oil as well as solutions at 1%, 2 %, 3%, 4% and 5% of CNSL were tested. Mean egg hatching rates varied significantly among treatments, ranging from 0.00 ± 0.00% (Neem oil and CNSL) (respectively at half recommended dose and 4%) to 100% (Control). Mortality of adult female T. evansi also differed significantly among treatments (P < 0.0001), ranging from 22.00 ± 4.20% to 100%. The highest mortality rates were recorded with Neem oil at any doses and with CNSL at 4%, whereas the lowest rate was recorded with the control treatment. Fecundity of pesticide-treated females T. evansi and proportion of eggs that hatched revealed significant differences among all doses of products (P < 0.0001). It appears from this study that even the half recommended dose of Neem oil and the CNSL at 4% were very effective on suppressing T. evansi populations and should, therefore, be subject to further studies to test their compatibility with natural enemies, and to determine strategies for their efficient applications in greenhouse and under field conditions.   &nbsp